The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some of such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.
Wireless communication systems are constantly under development. Developing systems provide a cost-effective support of high data rates and efficient resource utilization. One communication system under development is the 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) Release 8. An improved version of the Long Term Evolution radio access system is called LTE-Advanced (LTE-A). The LTE and LTE-A are designed to support various services, such as high-speed data.
In modern communication and computer networks, data exchange between programs and computers is a vital element. Different programs, computers and processors exchange data without human intervention. The number of devices or machines requiring cellular access without user activity will greatly increase in the future. Examples of such devices or machines include smart meters and sensors. These kinds of machines are stationary and may require only limited communication features.
In 3GPP a new device class has been proposed to describe for such machine-type communications (MTC) which has very limited set of features like supporting only few modulation and coding schemes, no mobility and few frequency bands, for example.
The stationary devices utilising machine-type communication may require network access on regular basis and are basically always (or very large proportion of their operation time) connected to same base station or eNodeB. Although they need seldom network access, the time period between the consecutive access attempts may vary quite much. In current LTE system, when user equipment which is connected to a base station or a eNodeB but has been inactive for long time is moved from a state with radio resource connection (RRC_CONNECTED) to an idle state (RRC_IDLE). This means that during the next connection attempt the user equipment has to perform RRC Connection Establishment procedure again. This is acceptable or natural when the user equipment is moving without a firm knowledge that when (and to what cell) the next connection attempt may occur: the user equipment context is released from the last serving eNodeB. However, MTC traffic characteristics may be such that a stationary device may send only few hundred bits at a time or per each access and then stay inactive for a long time. Thus a device may send several small packets at very random intervals. Between consecutive transmission occasions it may go into RRC_IDLE and it would have to go through the full RRC Connection Establishment procedure again for just to transmit again few hundred bits. As a result, transmitting small amount of information requires lots of signalling and protocol overhead in MTC.